Deductions from the Given Information

The main deduction that we want to make is that the shape on the right can be divided into two smaller shapes: a rectangle and a right triangle (see diagram below).

Solving the Problem

Quantity A can be solved simply by multiplying $8$ and $3$ together to get $24$. And now that we have divided the other shape into two smaller shapes, we can calculate its area. The area of the rectangular region is $4 \times 5 = 20$ and the area of the right triangle is $\frac{4 \times 2}{2} = 4$. Adding these two regions together we get $20+4=24$ for Quantity B.

Thus, the answer is C, The two quantities are equal.